TENNIS: Most of us will never know what it's like to play against your sibling at sport's highest level.
Sure, plenty have played hard-fought games of backyard cricket against brothers and sisters, ruined clothes and broken bones in games of touch football that evolved into tackle and may have even smashed a racquet or two during what should have been a friendly game of tennis.
Siblings everywhere can attest to just how hard it is to keep your cool during what are effectively meaningless contests played out in backyards and parks around the world.
It's this knowledge that makes the Williams sisters so special.
Sure, they're gun tennis players - that much is obvious - but just as impressive as their racquet-wielding ability is how they carry themselves under the halo of victory or with the disappointment of defeat on the biggest stage of all.
Serena won grand slam trophy number 23 by beating Venus 6-4 6-4 in the final of the Australian Open on Saturday night - the seventh time she's won the decider at Melbourne Park.
She's now moved past Steffi Graf to become the woman with the most major singles crowns in the Open era. She only sits behind Margaret Court (24) in terms of all-time grand slam wins.
But for all the plaudits that will flow Serena's way in the aftermath of her history-making win, both women deserve praise for what went on after the match.
Venus went around to the other side of the net and embraced Serena in a lengthy, warm hug. In their post-match speeches, each spent more time praising the other than focusing on their own achievements. It was all class.
Serena and Venus tried to outdo each other on the court, and they were at it again on the dais during the post-match presentation.
It was as if each sister wanted to be the most polite, the most gracious and the most humble. Simply, there was some classy sportsmanship on show.
"Serena Williams - that is my little sister guys," Venus said. "Your win has always been my win. I think you know that.
"All the times I wasn't there or couldn't be there or didn't get there, you've been there.
"I'm enormously proud of you, you mean the world to me."
Asked in her press conference if it was difficult to be happy for her sister because she was disappointed she didn't win, Venus' response was exactly what you'd expect.
"No, because I guess I've been here before, you know. I really enjoy seeing the name Williams name on the trophy. This is a beautiful thing."
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